Hello everyone, my network worker friends
Generally, if you encounter a problem that you cannot access the Internet, what will you do?
Maybe try to use the ping command to test whether the network is normal, right?
But sometimes it will happen that the ip can be pinged, but the Internet cannot be accessed . Most network workers should have encountered this situation.
If it can be pinged, it means that the ip can communicate with the network device, but if it cannot access the network, it is necessary to analyze the specific problem in detail.
Let’s talk about the basics today. The ip can be pinged but the Internet cannot be accessed. What’s the problem?
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01 IP conflict
The so-called ip conflict is due to two identical ip addresses appearing in the network.
The network is very unstable, sometimes it can be pinged, and sometimes it can’t be pinged, causing several devices in the network to be unable to connect to the network, especially in a small-scale monitoring project or office network, it is most likely to happen.
Let's see how to solve it:
You can click "Start" → "Run" in the lower left corner, type: ipconfig /release, and click "OK" to release the ip address.
At this time, the network will be disconnected, because the ip address has been released.
Click "Start" → "Run" again, type: ipconfig /renew, click "OK" to obtain the IP address again, and the IP address conflict can be resolved.
At this time, the network will be reconnected, but the ip address is different from the original one, and the available ip address has been reassigned to connect to the network.
02 No fixed IP
In many cases, everyone uses the method of automatically obtaining ip, and the DHCP service is often enabled in the project, so the ip is basically obtained automatically.
The ip is not fixed, and if something goes wrong, it is difficult to locate which device is the cause.
So how to bind ip address and mac physical address?
First enter cmd to enter the command configuration symbol, and then enter the command ipconfig/all to check the local ip and mac addresses.
Enter the command "arp -s 10.168.1.143 36-F3-9A-2B-9E-13" to bind.
Then enter the command arp -a to check whether the binding is successful.
Obviously, the default gateway address 10.168.1.143 is successfully bound to 36-F3-9A-2B-9E-13, and the MAC address is on it.
If other workstations try to use the 10.168.1.143 address when surfing the Internet in the future, there will be a failure phenomenon that they cannot access the Internet. In this way, the operation stability of the entire LAN can be guaranteed.
03 Reasons for network equipment
It can be pinged in the project, but it cannot be accessed, or there is a delay, which is also related to the switch and router used. The main possible reasons are:
1. The capacity of the switch is too large, fully loaded, unable to process a lot of data at the same time, and a failure occurs.
2. The selection of switches does not match. In many large-scale monitoring projects, the core switch or aggregation layer switch does not calculate the backplane bandwidth and packet forwarding rate, or uses some low-end brands, resulting in low work efficiency and cannot be used normally.
3. The network equipment is old and its performance is low.
Generally speaking, when the ip address can be pinged, but cannot access the Internet, you need to take some measures to try to solve it.
Probably first check if there is any IP conflict, and whether the gateway is set correctly. Then check whether there is a fixed ip, server, firewall settings, and whether the network equipment is working properly. Step by step troubleshooting, find and solve the problem.
Finishing: Lao Yang 丨 10-year senior network engineer, more network workers to improve dry goods, please pay attention to the official account: Network Engineer Club